Now, Braley's quest for a third term serves as a test case of how well a Midwestern Democrat — running unapologetically on President Barack Obama's agenda — can weather the Republican resurgence.

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Count this Rahm Emanuel recruit as one of the rare Democrats in a competitive seat who is standing with Obama — not running away from him.

"It is a referendum on President Obama because he was elected here in Iowa with an overwhelming majority, one of the highest majorities of any president in recent history," Braley said Friday in a joint appearance with his GOP opponent Ben Lange on Iowa Public Television.

Lange, an attorney and former aide to Minnesota Rep. John Klein, rarely invokes the president's name, but is determined to shape the contest around Braley's votes for the stimulus package, health care and cap and trade.

"I use the statistic all the time, 98 percent in line with Nancy Pelosi. It's not about me. It really is about what Bruce has done," Lange said in an interview with POLITICO, referring to the House speaker. "He made decisions that were unpopular."

For most of the summer, Democrats here didn't appear to be overly concerned about that argument resonating in a district Obama carried by 17 percentage points two years ago, in a state that set him on the path to the White House. Braley had promised to "get things done" when he was hand-picked by Democrats to run for the open seat four years ago, and his party believed his profile as a level-headed populist who is intensely attentive to constituent service would help him survive any Republican wave this year.

Then the Des Moines-based conservative American Future Fund announced late last month it would spend $800,000 on television ads in the relatively inexpensive 1st Congressional District, which runs from Dubuque 90 miles west to Waterloo.

"If they were looking to get our attention, they did," acknowledged Iowa Democratic party chairwoman Sue Dvorksy. "You cannot let that much money go unanswered in media."